This invention relates generally to X-ray inspection systems and more particularly to collimators for such systems.
It is known to use linear detectors with X-ray inspection systems for industrial parts. Linear detectors can provide improved contrast resolution and are thus well suited for digital radiography (DR) and computed tomography (CT). Additionally, improved contrast resolution is achieved by the use of X-ray collimation, which reduces the contribution of scattered X-rays to the resulting image. Ideally, the X-ray source is vertically collimated to provide a flat X-ray beam plane, which defines an inspection zone on the part being inspected. Unfortunately, there is vertical spreading of the X-ray beam from the X-ray focal spot. This exposes the part to X-rays outside of the desired inspection zone which in turn contributes X-ray scatter. To minimize spreading, the size of the source collimator aperture can be reduced, but this can result in vertical masking of the x-ray focal spot, which reduces the effective output of the X-ray source and therefore increases part inspection time. Vertical collimation can also be provided between the target and the X-ray detector, but this approach increases the distance between the part and the detector, which reduces the effectiveness of the collimation. It also reduces the effective field of view of the inspection (and thus the inspectable part size) and increases the effects of focal spot blurring.
Accordingly, there is a need for an X-ray inspection system which incorporates effective collimation while efficiently utilizing the output of the X-ray source.
The above-mentioned need is met by the present invention, which provides an X-ray inspection system having an X-ray source and first and second collimators. The first and second collimators are arranged in relation to the source and the target such that the portion of the target actually illuminated by The X-ray beam is substantially equal to the size of a selected inspection zone.
The present invention and its advantages over the prior art will become apparent upon reading the following detailed description and the appended claims with reference to the accompanying drawings.